Supplemental Material
Supplementary Captions
Table S1. COVID-19 movement control order measures (Bernama, 2020a; Bernama 2020b;
Md Shah et al., 2020; Prime Minister’s Office, 2020a; Prime Minister’s Office, 2020b)
Table S2. Average concentration, variations before and during MCOs and relative change (%) of: PM2.5, CO, NO2, and SO2 for sub-urban stations.
Table S3. Average concentration, variations before and during MCOs and relative change (%) of: PM2.5, CO, NO2, and SO2 for urban stations.
Table S4. Average concentration, variations before and during MCOs and relative change (%) of PM2.5, CO, NO2, and SO2 for Industrial stations.
Table S5. Average concentration, variations before and during MCOs and relative change (%) of: PM2.5, CO, NO2, and SO2 for rural stations.
Table S1. COVID-19 movement control order measures (Bernama, 2020a; Bernama 2020b; Md Shah et al., 2020; Prime Minister’s Office, 2020a; Prime Minister’s Office, 2020b)
Date Measures Location January 25, 2020 First case of COVID-19 reported in Malaysia Johor March 18 – March Movement Control Order Phase 1 Entire country 31, 2020 All mass gathering is prohibited All business services and educational institution were closed except for essential ones (e.g., water, electricity, energy, telecommunications, postal, transportation, banking, health, pharmacy, airport, safety, defense, cleaning, retail, and food supply) All citizens have been prohibited from leaving the country Foreigners/ visitors restricted from entering the country March 27 – April, 14 Enhanced Movement Control Order (EMCO) Simpang Renggam, 2020 All residents and people who were in the areas Johor are not allowed to leave and no one can enter during the EMCO period. All business activities had been ordered to close. Roadblocks have been set-up and all entrance and exit points to the area had also been closed. Drones were deployed to monitor the movement of the residents in the area. Enhanced Movement Control Order (EMCO) Selangor Mansion and All residents and people who were in the areas Malayan Mansion are not allowed to leave and no one can enter buildings during the EMCO period. All business activities had been ordered to close except for shops selling essential items in the buildings All entrance and exit points to the area had also been closed March 30- April 13, Enhanced Movement Control Order (EMCO) Sungai Lui, Hulu 2020 All residents and people who were in the areas Langat Selangor are not allowed to leave and no one can enter during the EMCO period. All business activities had been ordered to close Roadblocks have been set-up and all entrance and exit points to the area had also been closed April 1 – April 14, Movement Control Order Phase 2 Entire Country 2020 Movements were restricted to a 10 kilometre radius from homes only to purchase or deliver food, daily necessities, and medicine. Businesses premises selling essential items including supermarkets and petrol stations are to operate from 8 am to 8 pm only. April 14 – April 28, Enhanced Movement Control Order (EMCO) Jalan Masjid India, 2020 All residents and people who were in the areas Kuala Lumpur are not allowed to leave and no one can enter during the EMCO period. All business activities had been ordered to close. All entrance and exit points to the area had also been closed. April 15 – April 28, Movement Control Order Phase 3 Entire Country 2020 School and universities had been told to implement online learning. Ministry of International Trade and Industry (MITI) has listed down several sectors that were allowed to operate with restricted conditions. All citizen was required to stay at home but were still allowed to go out and get essential supplies April 29 – May 3, Movement Control order Phase 4 Entire Country 2020 Movements were still restricted to a 10- kilometre radius from homes only to purchase or deliver food, daily necessities, and medicine. Students stranded at the university were allowed to go home with proper guidelines (stage by stage and only using buses that is provided by the university management May 4, 2020 – 9 June Conditional Movement Control Order Entire Country 2020 (CMCO) starts Movements were restricted by state borders Interstate movement for stranded person were allowed on 7 May until 10 May only.
Table S2. Average concentration, variations before and during MCOs and relative change (%) of: PM2.5, CO, NO2, and SO2 for sub-urban stations.
-3 PM2.5 (µg m ) CO (ppm) NO2 (ppm) SO2 (ppm) Stations Region Before Before Before Before MCOs % MCOs % MCOs % MCOs % MCO MCO MCO MCO
Kangar N 12.96 10.5 -18.94+ 0.4707 0.4360 -7.36+ 0.0027 0.0015 -44.65+ 0.0005 0.0008 56.64+
Langkawi N 12.97 9.81 -24.34+ 0.4319 0.2759 -36.13+ 0.0042 0.0019 -55.38+ 0.0008 0.0011 30.09+
Alor Setar N 20.16 11.3 -43.93+ 0.5128 0.4962 -3.23 0.0049 0.0032 -35.43+ 0.0007 0.0005 -24.26+
Sg Petani N 19.01 11.84 -37.71+ 0.4425 0.3270 -26.10+ 0.0072 0.0044 -38.94+ 0.0007 0.0007 10.56+
Seberang Perai N 21.24 12.37 -41.76+ 0.7077 0.5120 -27.66+ 0.0072 0.0046 -36.72+ 0.0007 0.0007 0.33
Balik Pulau N 19.45 13.88 -28.65+ 0.5633 0.4263 -24.33+ 0.0039 0.0027 -30.25+ 0.0006 0.0008 29.64
Taiping N 25.25 11.75 -53.47+ 0.2407 0.1997 -17.04 0.0087 0.0041 -52.38+ 0.0011 0.0010 -2.66
Pegoh Ipoh N 18.87 15.09 -20.03+ 0.4181 0.3335 -20.24+ 0.0067 0.0037 -44.04+ 0.0003 0.0008 172.48+
Tg Malim N 9.52 7.36 -22.73+ 0.5198 0.4303 -17.22+ 0.0055 0.0026 -53.43+ 0.0005 0.0007 39.61
Batu Muda KL C 21.47 17.81 -17.02 1.1525 0.8349 -27.55+ 0.0161 0.0053 -67.16+ 0.0007 0.0005 -33.67+
Putrajaya C 21.96 16.23 -26.12+ 0.7058 0.4818 -31.74+ 0.0077 0.0037 -52.36+ 0.0011 0.0011 -0.61
Petaling Jaya C 25.49 16.45 -35.47+ 1.2540 0.5839 -53.43+ 0.0258 0.0082 -68.26+ 0.0009 0.0007 -23.80+
Klang C 25.57 22.17 -13.28 0.9501 0.6162 -35.14+ 0.0183 0.0087 -52.60+ 0.0010 0.0009 -10.42
Banting C 20.47 15.49 -24.34+ 0.7939 0.5151 -35.12+ 0.0101 0.0058 -42.52+ 0.0014 0.0012 -15.29+
Nilai S 23.53 15.78 -32.93+ 0.5377 0.3942 -26.68+ 0.0133 0.0067 -49.44+ 0.0011 0.0009 -20.62+
Port Dickson S 16.56 12.36 -25.37+ 0.5878 0.5170 -12.05+ 0.0073 0.0039 -46.90+ 0.0022 0.0011 -51.83+
Bukit Rambai S 15.8 12.39 -21.56+ 0.5253 0.4301 -18.12+ 0.0061 0.0036 -41.76+ 0.0012 0.0013 9.64
Segamat S 14.47 15.84 9.46 0.5606 0.5231 -6.69 0.0030 0.0029 -4.04+ 0.0011 0.0013 18.63
Batu Pahat S 12.87 10.13 -21.31+ 0.6688 0.5025 -24.87 0.0051 0.0028 -45.43+ 0.0019 0.0019 3.50
KotaTinggi S 8.08 7.2 -10.90+ 0.3905 0.4596 17.69 0.0017 0.0018 6.87+ 0.0008 0.0010 38.36
Tangkak S 14.81 11.3 -23.70+ 0.7606 0.5423 -28.71+ 0.0055 0.0027 -51.58+ 0.0009 0.0009 0.17
Temerloh E 14.61 12.38 -15.23+ 0.4509 0.3741 -17.02+ 0.0042 0.0020 -51.62+ 0.0009 0.0006 -33.46+
Jerantut E 15.52 10.25 -33.94+ 0.3113 0.3585 15.17+ 0.0026 0.0014 -47.56+ 0.0007 0.0005 -34.03+
Indera E 9.25 8.35 -9.68+ 0.3745 0.3810 1.72+ 0.0046 0.0019 -58.09+ 0.0012 0.0007 -39.57 Mahkota
Besut E 12.84 11.83 -7.89 0.6305 0.4821 -23.53+ 0.0018 0.0014 -23.30 0.0010 0.0007 -26.42+
Tanah Merah E 22.82 18.74 -17.87+ 0.6739 0.5478 -18.72 0.0052 0.0029 -44.85+ 0.0010 0.0008 -22.04+
Kota Bharu E 14.84 15.2 2.4 0.4208 0.4001 -4.91 0.0032 0.0023 -28.04+ 0.0012 0.0008 -29.27+
Tawau Sb 7.06 6.76 -4.23 0.5314 0.5864 10.34+ 0.0042 0.0027 -36.46+ 0.0005 0.0004 -15.49+ Sandakan Sb 11 9.09 -17.31+ 0.6142 0.5039 -17.96 0.0035 0.0016 -53.85+ 0.0007 0.0008 16.04+
Kota Kinabalu Sb 11.76 9.35 -20.51 0.5122 0.5564 8.64+ 0.0031 0.0012 -62.21+ 0.0016 0.0007 -52.73+
Labuan L 12.08 13.59 12.47 0.9920 0.6185 -37.65+ 0.0022 0.0014 -35.78+ 0.0008 0.0011 24.28+
Miri Sr 15.26 13.37 -12.43 0.5398 0.5366 -0.59 0.0040 0.0019 -51.22+ 0.0005 0.0005 1.00
Bintulu Sr 13.48 12.56 -6.8 0.4515 0.4457 -1.29 0.0042 0.0030 -29.41+ 0.0005 0.0003 -44.25
Sibu Sr 10.42 8.86 -14.98+ 0.2704 0.2435 -9.96 0.0041 0.0021 -49.35+ 0.0008 0.0009 17.34+
+ indicate average concentration before MCO vs average concentration during MCOs significant at p<0.05; NA: not available.
Table S3. Average concentration, variations before and during MCOs and relative change (%)
of: PM2.5, CO, NO2, and SO2 for urban stations.
-3 PM2.5 (µg m ) CO (ppm) NO2 (ppm) SO2 (ppm)
Stations Region Before Before Before Before MCOs % MCOs % MCOs % MCOs % MCO MCO MCO MCO
Seberang Jaya N 23.94 14.24 -40.51+ 0.8144 0.5786 -28.95+ 0.0131 0.0070 -46.46+ 0.0011 0.0009 -13.63+
Minden N 21.48 11.51 -46.43+ 0.6121 0.4764 -22.17+ 0.0085 0.0043 -49.79+ 0.0010 0.0009 -4.24
TasekIpoh N 19.73 14.24 -27.83+ 0.6512 0.4859 -25.37+ 0.0090 0.0035 -60.62+ 0.0009 0.0008 -2.99
Cheras C 21.35 14.5 -32.06+ 0.8069 0.5606 -30.53+ 0.0148 0.0051 -65.56+ 0.0004 0.0006 38.49+
Shah Alam C 19.77 16.12 -18.45+ 0.8392 0.6217 -25.92 0.0130 0.0065 -49.52+ 0.0012 0.0010 -13.12
Seremban S 13.96 11.61 -16.82+ 0.6157 0.4864 -20.99+ 0.0068 0.0027 -61.10+ 0.0008 0.0010 25.19
Bandaraya S -11.74+ 0.5487 0.5167 -5.83 0.0058 0.0033 -43.19+ 0.0008 0.0009 10.09 Melaka 14.25 12.58
Larkin S 14.3 13.4 -6.34 0.4559 0.3134 -31.25+ 0.0083 0.0041 -50.92+ 0.0018 0.0019 8.45+
Pasir Gudang S 10.6 10.76 1.5 0.5050 0.4718 -6.56+ 0.0047 0.0046 -1.66+ 0.0010 0.0011 13.22
Kuala E -4.93 0.5581 0.4595 -17.66 0.0040 0.0022 -43.63+ 0.0012 0.0009 -22.43+ Terengganu 15.7 14.92
Kuching Sr 9.13 8.43 -7.6 0.5564 0.5946 +6.86 0.0039 0.0024 -39.71+ 0.0002 0.0003 +61.15
+ indicate average concentration before MCO vs average concentration during MCOs significant at p<0.05; NA: not available.
Table S4. Average concentration, variations before and during MCOs and relative change (%) of: PM2.5, CO, NO2, and SO2 for industrial stations.
-3 PM2.5 (µg m ) CO (ppm) NO2 (ppm) SO2 (ppm)
Stations Region Before Before Before Before MCOs % MCOs % MCOs % MCOs % MCO MCO MCO MCO
Kulim N 20.18 11.21 -44.46+ NA NA NA 0.0084 0.0047 -44.33+ 0.0010 0.0011 10.23
Pengerang S 8.44 10.4 23.1800 NA NA NA 0.0027 0.0029 6.28 0.0013 0.0015 19.91+
Balok Baru E 12.05 9.15 -24.07+ NA NA NA 0.0058 0.0028 -51.85+ 0.0019 0.0006 -65.97
Kemaman E 16.47 11.27 -31.54+ NA NA NA 0.0023 0.0018 -19.02+ 0.0007 0.0008 21.64
Paka E 10.4 7.83 -24.72+ NA NA NA 0.0014 0.0009 34.61 0.0007 0.0007 -2.92+
Kimanis Sb 10.45 10.65 1.9900 NA NA NA 0.0020 0.0011 -46.38+ 0.0008 0.0007 -5.24+
Samalaju Sr 10.84 9.81 -9.5200 NA NA NA 0.0019 0.0016 -13.90 0.0010 0.0005 48.18
+ indicate average concentration before MCO vs average concentration during MCOs significant at p<0.05; NA: not available.
Table S5. Average concentration, variations before and during MCOs and relative change (%) of: PM2.5, CO, NO2, and SO2 for rural stations.
-3 PM2.5 (µg m ) CO (ppm) NO2 (ppm) SO2 (ppm)
Stations Region Before Before Before Before MCOs % MCOs % MCOs % MCOs % MCO MCO MCO MCO
Seri Manjung N 18.35 14.16 -22.85+ NA NA NA NA NA NA NA NA NA
Kuala Selangor C 15.54 14.27 -8.16+ NA NA NA NA NA NA NA NA NA
Alor Gajah S 11.52 10.71 -6.99 NA NA NA NA NA NA NA NA NA
Kluang S 9.22 8.03 -12.81 NA NA NA NA NA NA NA NA NA
Rompin E 9.12 12.1 32.74 NA NA NA NA NA NA NA NA NA
Limbang Sr 8.6 7.16 -16.69+ NA NA NA NA NA NA NA NA NA
Miri Sr 12.53 9.76 -22.14+ NA NA NA NA NA NA NA NA NA
Mukah Sr 6.78 6.42 -5.34 NA NA NA NA NA NA NA NA NA
Kapit Sr 6.38 6.34 -0.54 NA NA NA NA NA NA NA NA NA
Sarikei Sr 8.3 5.82 -29.91+ NA NA NA NA NA NA NA NA NA
Seri Aman Sr 7.32 6.56 -10.39 NA NA NA NA NA NA NA NA NA
Samarahan Sr 6.43 6.91 7.4 NA NA NA NA NA NA NA NA NA
+ indicate average concentration before MCO vs average concentration during MCOs significant at p<0.05; NA: not available.
Figure Captions
Fig. S1. Temporal variations of meteorological parameters during study periods.
Fig. S1.